Steel alloy



fl STATES.

' than GEORGE L. NORRIS,

015! SUMMIT, HIE-V87 JERSEY, ASSIGNOR TO VANADIUM CORPORATION OF AMERICA, A CORPORATION OF DELAWARE.

STEEL ALLOY.

No Drawing.

This invention relates to alloy steels and particularly to steels containing Sll'COIl in somewhat greater proportion than the ordinary steels of commerce. V

The addition of silicon to steel is known to have a beneficial effect. Steels contain ng relatively high proportions of slllcon have, however, the disadvantage of being very .sensitive to heat treatment. thatus to say,

the temperature range within which certain desirable physical properties can be obtained by quenching and drawing is .relatively limited. Moreover, the silicon steels heretofore known lack the h gh" tenslle strength, toughness and resistance to alternating stresses and shocks which are essential to meet the conditions in certain uses of such'steels.

It is the object of the present invent on to i provide an improved silicon steel which is adapted especially for use in various structural parts of boilers, pressure tanks, stills and hulls, engine and machinery parts, springs, bolts and tools, and is' designed particularly. to meet the peculiar stresses to which such parts are subjected.

Other objects and advantages of the invem tion will be apparent as it'is better understood by referencetg the following specifica- 0 tion in which the preferred compositions are described.

I have. discovered that the addition of" vanadium to silicon steels, and particularly to steels of the composition hereinafter described, results in' a very material improvement in the quality and characteristics of the product. The vanadium increases the.

ratio of elastic limit to tensile strength, the ductility and shock resistance of the steel, 40 thus making it suitable for various uses to which such steel has not been well adapted heretofore. The vanadium also overcomes the well known tendency of silicon to cause separation of carbon in the steel in the form 4.5 of graphite and consequent injury 'to the physical properties of the steel. As the result of the improvement it is possible to construct parts of lighter weight with the same or greater physical strength than parts made to of steel as heretofore known. The addition of vanadium results,- therefore, in the productiou of steels whicl 1 afi'ord conside able Application flled' January 19,1927. Serial No. 162,208.

qualities of steels with relatively high carbon content. The proportions of silicon, manganese and vanadlum may likewise vary within the comparatively wide ranges indicated to produce steels having the desired qualities,

and characteristics to adapt them for the special uses for which they are intended.

I have discovered also that the steels as described maybe further improved by the addition of nickel preferably in amount not exceeding 1.5% or copper not in excess of 0.5%. These elements are especially beneficial in increasing the corrosion resistance of the, steel without adversely affecting the physical properties which result from the presence of silicon and vanadium.

The improved steels can be produced by "any of the well known steel-making processes. The silicon and vanadium can be added in the form of ferro-alloys in the usual manner to the ladle during the tapping of the steel from the furnace, or in the case of electric furnace and acid open hearth furnace steel, the ferrosilicon and ferrovanadium maybe added to the molten bath of steel in the furnace with a short interval, suflicient to allow them to melt, before tapping. It is desirable to reladle the steel, that is, pour from one ladle into another before casting the steel into molds. This is particularly desirable when the ferrosilicon and ferrovanadium are added to the ladle in order to secure greater uniformity, lessen the possibility of segregation, and reduce the amount of plping in the ingot, all of which are influenced by the large percentage of silicon added.

l have also discovered that steels containing silicon can be improved, with respect to 'physical properties and particularly as to the ratio of elastic limit to tensile strength, ductility and shock resistance by the addition of molybdenum in suitable proportions to a steel having the composition, for example, of silicon 0.40% to 1.25%, manganese 0.20% to 0.40%, and carbon 0.10% to0.30%.'

To such a steel I find .it advanta eous to add from 0.10% to 1.00% of molybdenum to obtain the desiredimprovement in the characteristics mentioned.

It is to .be understood that the steels as described may include the usual impurities such as sulphur and phosphorus in the procations or in amounts which are not detri-- portions permitted by standard steel specimental to the qualities of the steel and that other elements may be present likewise either GEORGE L. NORRIS. 

